Curable silicone composition, release coating agent comprising said composition, release film obtained using said release coating agent, and layered product including said release film

ABSTRACT

Provided is a curable silicone composition for a release agent which can form a release film having a silicone adhesive with a low release force even when thin and which does not reduce the adhesive strength of the silicone adhesive to other substrates upon releasing the release film. A release film and laminate are also provided. The curable silicone composition comprises: (A) a fluorine-containing organopolysiloxane mixture obtained by mixing the following components (A1) and (A2) at a mass ratio of 1/99 to 45/55: (A1) a fluoro(poly)ether modified organopolysiloxane having at least two alkenyl groups per molecule along with a fluoro(poly)ether-containing organic group; (A2) a fluoroalkyl group-containing organopolysiloxane having at least two alkenyl groups per molecule along with a fluoroalkyl group having 1 to 12 carbon atoms; (B) an organopolysiloxane having at least three silicon atom-bonded hydrogen atoms per molecule; (C) a hydrosilylation reaction catalyst; and (D) an organic solvent.

TECHNICAL FIELD

The present invention relates to a curable silicone composition, arelease coating agent consisting of the composition, specifically, arelease coating agent for a silicone adhesive (pressure sensitiveadhesive), a release film using the release coating agent, specifically,a release film for a silicone adhesive, and a laminate including therelease film, specifically, a laminate including the release film andthe silicone adhesive.

BACKGROUND ART

Silicone adhesives (pressure-sensitive adhesives) have been widely usedas adhesives for industrial protective tapes, masking tapes, etc. orvarious medical functional tapes due to the excellent heat resistance,cold resistance, weather resistance, chemical resistance, and electricalinsulation thereof, etc. Moreover, in recent years, silicone adhesiveshave been used for so-called assembly applications represented byoptical components for liquid crystal displays (display devices,functional films, lenses, etc.). Since silicone adhesives stronglyadhere to surfaces coated with silicone rubber or silicone-basedmaterials, normal silicone based release agents used in acrylic andorganic rubber based adhesives cannot be used, with various curablesilicone release agent compositions having been proposed to form arelease film enabling the easy release of the silicone adhesive. Thecomposition is coated on a flexible substrate such as a plastic film asa release coating agent to form a release film, which is used as alaminate of a sheet or rolled tape adhered together with a siliconeadhesive.

When the release film is released from such a laminate and used, a lowerstable release force is required in order to increase the workingefficiency and prevent surface roughness of the silicone adhesive uponrelease.

In contrast, the adhesive force of the silicone adhesive released fromthe release film preferably has low adverse effects such as a reductionin the adhesive force caused by long-term adhesion with the releasefilm.

For example, as a release agent composition for a silicone adhesive,Patent Document 1 proposes a curable coating composition including: anorganopolysiloxane having at least 300 silicon atoms, from 0.5 to 2 mole% of a vinyl group-containing siloxane unit, and 30 mole % of afluoroalkyl group-containing siloxane unit; anorganohydrogenpolysiloxane having an average of at least two siliconatom-bonded hydrogen atoms in each molecule in addition to beingcompatible with the organopolysiloxane; a hydrosilylation reactioncatalyst; and a hydrosilylation reaction inhibitor.

Moreover, Patent Document 2 discloses a release agent composition for asilicone adhesive which includes: an organopolysiloxane having at leasttwo alkenyl group-containing organic groups bonded to silicon permolecule and containing at least one fluorine-containing substituent(selected from the group consisting of multiple fluoro(poly)ethergroups) bonded to silicon atoms per molecule; anorganohydrogenpolysiloxane having at least three silicon atom-bondedhydrogen atoms per molecule; and a hydrosilylation reaction catalyst.

Further, Patent Document 3 proposes a release agent composition for asilicone adhesive including two fluoroalkyl-modifiedpolydimethylsiloxanes having different amounts of alkenyl groups for thepurpose of light release, as well as a release sheet formed by applyingthe release agent composition to a substrate.

Furthermore, Patent Document 4 proposes a silicone composition forforming a different release agent for a silicone adhesive containing: anorganohydrogenpolysiloxane which, per molecule, contains at least twoalkenyl groups bonded to silicon atoms, and at least one fluoroalkylgroup and fluoropolyether group as two fluorine-containing substituentsbonded to silicon atoms (wherein, the content of fluoropolyether groupsrelative to the total of fluoroalkyl groups and fluoropolyether groupsis 1 to 99 mole %); an organohydrogenpolysiloxane having at least threehydrogen atoms bonded to silicon atoms per molecule; and aplatinum-group metal-based catalyst. Moreover, in this example, thecomposition includes an organopolysiloxane having at least onefluoroalkyl group and fluoropolyether group as two fluorine-containingsubstituents bonded to silicon atoms, wherein a composition whichincludes an organopolysiloxane having only a3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl group as afluorine-containing substituent along with an organopolysiloxane havingonly a fluoropolyether group as a fluorine-containing substituent isprepared to compare the release performance.

PRIOR ART DOCUMENTS Patent Documents

Patent Document 1: Japanese Unexamined Patent Application PublicationNo. H2-245031

Patent Document 2: Japanese Unexamined Patent Application PublicationNo. H1-74268

Patent Document 3: Japanese Unexamined Patent Application PublicationNo. 2005-60554

Patent Document 4: Japanese Unexamined Patent Application PublicationNo. 2017-165893

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

However, there is a demand for further improvement in order to solve theproblem in which even when a release film, as well as a laminate, isformed using a conventionally known composition as a release coating,the release film can be released from the silicone adhesive with a lowerrelease force, and further, the adhesive force of the silicone adhesiveto other substrates upon releasing the release film is not reduced asmuch as possible.

Moreover, when a composition including an organopolysiloxane having onlya fluoroalkyl group and an organopolysiloxane having only afluoropolyether group, at a mass ratio of 1:1, is used, as described inPatent Document 4 as a comparative example, it is problematic in thatthe release force value when releasing the release film from thesilicone adhesive is not stable and the surface of the silicone adhesiveafter release is roughened.

An object of the present invention is to provide: a release film whichcan be released from a silicone adhesive (also referred to as a siliconepressure sensitive adhesive) (which is adhered to a thin layer even whenthe release layer is a thin layer) with a low release force, has astable release force with respect to the silicone adhesive, and does notsignificantly reduce the adhesive force of the silicone adhesive uponreleasing the release film after adhering together the release film,compared with the case in which the release film has not been adheredtogether; a release agent for such a release film; a curable siliconecomposition which can be used as a release agent; and a laminate whichincludes a substrate, a silicone adhesive layer, and a release agentlayer. Note that the release film generally includes a release layerformed by coating a release agent on a flexible substrate such as aplastic film.

Means for Solving the Problems

The present inventors found that the abovementioned problems can besolved by using a release agent which is obtained by combining: afluoro(poly)ether-modified organopolysiloxane as a fluorine-containingorganopolysiloxane having at least two alkenyl groups per molecule alongwith a fluoro(poly)ether-containing organic group; and a fluoroalkylgroup-containing organopolysiloxane having at least two alkenyl groupsper molecule along with a fluoroalkyl group having 1 to 12 carbon atoms,at a mass ratio of 1/99 to 45/55, thereby completing the presentinvention.

The curable silicone composition of the present invention contains:

(A) a fluorine-containing organopolysiloxane mixture obtained by mixingthe following components (A1) and (A2) at a mass ratio (components(A1)/(A2)) of 1/99 to 45/55:(A1) a fluoro(poly)ether modified organopolysiloxane having at least twoalkenyl groups per molecule along with a fluoro(poly)ether-containingorganic group;(A2) a fluoroalkyl group-containing organopolysiloxane having at leasttwo alkenyl groups per molecule along with a fluoroalkyl group having 1to 12 carbon atoms;(B) an organopolysiloxane having at least three silicon atom-bondedhydrogen atoms per molecule;(C) a hydrosilylation reaction catalyst; and(D) an organic solvent.

Component (A) preferably includes components (A1) and (A2) at a massratio of 2/98 to 40/60.

Component (B) is preferably an organopolysiloxane having a fluoroalkylgroup with 1 to 12 carbon atoms or a fluoro(poly)ether-containingorganic group.

Component (D) is preferably a solvent mixture consisting of one solventor two or more solvents selected from the group consisting of diethylether, dipropyl ether, diisopropyl ether, dibutyl ether, diisobutylether, di-sec-butyl ether, di-tert-butyl ether, methyl-tert-butyl ether,ethyl-tert-butyl ether, pentane, m-xylene hexafluoride,methylheptafluoropropyl ether, methylnonafluorobutyl ether,ethylnonafluorobutyl ether, and3-methoxy-1,1,1,2,2,3,4,4,5,5,6,6,6-tridecafluoro hexane.

The curable silicone composition according to the present inventionpreferably further includes (E) a hydrosilylation reaction controlagent.

The present invention further provides a release coating agent, whereinthe release coating agent according to the present invention consists ofthe abovementioned curable silicone composition. The release coatingagent according to the present invention can further include anadditive.

In one aspect of the present invention, the release coating agent is arelease coating agent for a silicone adhesive.

The present invention relates to a release film including: a film-likesubstrate; and a release layer consisting of a cured product obtained bycuring the release coating agent.

The substrate is preferably a plastic film and is also preferably lighttransmissive.

The release layer preferably has a thickness of 0.5 μm or less.

In one aspect of the present invention, the release film is a releasefilm for silicone adhesives.

The present invention further provides a laminate using theabovementioned release coating agent. In one aspect of the presentinvention, the laminate is a laminate including a structure in which asilicone adhesive layer is disposed so as to face at least one releaselayer, wherein the release layer is a release layer consisting of acured product formed by curing the release coating agent. Moreover, therelease film according to the present invention includes a film-likesubstrate and a release layer. Moreover, the laminate includes alaminate structure configured to include a silicone adhesive disposed onthe release layer, in addition to including: a laminate which includesan adhesive formed by a curing reaction on the release layer; and alaminate formed by adhering together a release layer to a previouslyformed adhesive.

Effects of the Invention

Upon using the curable silicone composition according to the presentinvention as a release coating agent, even if the thickness of therelease layer is thin, a release film can be formed in which thesilicone adhesive adhered on the release layer can be released from therelease layer with a low release force. Moreover, the release film andlaminate according to the present invention can stably release asilicone adhesive disposed on the release layer (including an adhesiveformed by a curing reaction on the release layer; and a laminate formedby adhering together a release layer to a previously formed adhesive)from the release layer with a low release force, such that the siliconeadhesive after release can have a uniform surface. Further, the adhesiveforce of the silicone adhesive can be maintained at a high proportioneven after the release layer is adhered and then released compared toprior to adhering the release layer according to the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross sectional view illustrating one embodiment of alaminate according to the present invention.

FIG. 2 is a cross sectional view illustrating one embodiment of alaminate according to the present invention.

FIG. 3 is a cross sectional view illustrating one embodiment of alaminate according to the present invention.

FIG. 4 is a cross sectional view illustrating one embodiment of alaminate according to the present invention.

MODE FOR CARRYING OUT THE INVENTION

The curable silicone composition of the present invention is describedbelow in detail.

[Curable Silicone Composition]

The curable silicone composition of the present invention contains:(A) a fluorine-containing organopolysiloxane mixture obtained by mixingthe following components (A1) and (A2) at a mass ratio of 1/99 to 45/55:(A1) a fluoro(poly)ether modified organopolysiloxane having at least twoalkenyl groups per molecule along with a fluoro(poly)ether-containingorganic group;(A2) a fluoroalkyl group-containing organopolysiloxane having at leasttwo alkenyl groups per molecule along with a fluoroalkyl group having 1to 12 carbon atoms;(B) an organopolysiloxane having at least three silicon atom-bondedhydrogen atoms per molecule;(C) a hydrosilylation reaction catalyst; and(D) an organic solvent.Optional components which may be further added to these essentialcomponents (A), (B), (C), and (D) will be described along with thecurable silicone composition.

[Component (A)]

Component (A) is a fluorine-containing organopolysiloxane mixtureobtained by mixing, at a mass ratio of 1/99 to 45/55: (A1) afluoro(poly)ether modified organopolysiloxane having at least twoalkenyl groups per molecule along with a fluoro(poly)ether-containingorganic group; and (A2) a fluoroalkyl group-containingorganopolysiloxane having at least two alkenyl groups per molecule alongwith a fluoroalkyl group having 1 to 12 carbon atoms. Component (A)includes components (A1) and (A2) at a mass ratio of 1/99 to 45/55, butpreferably includes components (A1) and (A2) at a mass ratio of 1.5/98.5to 40/60, more preferably at a mass ratio of 2/98 to 40/60, andparticularly preferably at a mass ratio of 2/98 to 35/65. Whencomponents (A1) and (A2) are used in combination, a release force isobtained that is lower than the release force for the silicone adhesive,which is estimated by arithmetic means, based on the results ofindependently using component (A1) or (A2) instead of component (A).

The molecular structure of components (A1) and (A2) is not limited.Examples thereof include a straight-chain structure, a branched-chainstructure, a partially branched straight-chain structure, a resinousstructure, and a cyclic structure, with a straight-chain structure or apartially branched straight-chain structure being preferable.

An example of such component (A1) is an organopolysiloxane representedby the following average unit formula (I):

(R¹ ₃SiO_(1/2))_(a)(R¹₂SiO_(2/2))_(b)(R¹SiO_(3/2))_(c)(SiO_(4/2))_(d)  (I)

(wherein, the R¹ moieties are the same or different and are eachindependently alkyl groups having from 1 to 12 carbon atoms, alkenylgroups having from 2 to 12 carbon atoms, aryl groups having from 6 to 12carbon atoms, aralkyl groups having from 7 to 12 carbon atoms, orfluoro(poly)ether-containing organic groups having from 2 to 30 carbonatoms, provided that per molecule, at least two R¹ moieties are alkenylgroups and at least one R¹ moiety is a fluoro(poly)ether-containingorganic group; a is a positive number; b is a positive number; c is 0 ora positive number; and d is 0 or a positive number.) Moreover, for a tod in the abovementioned formula (I), a is an integer of 2 or more,preferably an integer of 2 to 6, b is an integer of 1 or more,preferably an integer of 1 to 5,000, more preferably an integer of 30 to3,000, c is 0 or a positive number, and d is 0 or a positive number.When the degree of siloxane polymerization is less than the lower limitof the range described above, when the curable silicone compositionobtained using this component is used as a release coating agent,formation of the release layer may be difficult, while when the degreeof siloxane polymerization exceeds the upper limit of the rangedescribed above, the coating properties (particularly thin filmapplicability) of the obtained curable silicone composition maydecrease. Note that in formula (I), R¹ may be a small amount of hydroxylgroups or alkoxy groups as long as it does not impair the object of thepresent invention.

Exemplary alkyl groups which may be represented by R¹ in formula (I)having 1 to 12 carbon atoms include methyl groups, ethyl groups, propylgroups, butyl groups, pentyl groups, hexyl groups, heptyl groups, octylgroups, nonyl groups, decyl groups, undecyl groups, and dodecyl groups,with methyl groups preferable.

Exemplary alkenyl groups which may be represented by R¹ in formula (I)having 2 to 12 carbon atoms include vinyl groups, allyl groups, butenylgroups, pentenyl groups, hexenyl groups, heptenyl groups, octenylgroups, nonenyl groups, decenyl groups, undecenyl groups, and dodecenylgroups, wherein alkenyl groups are preferably vinyl groups or hexenylgroups, with vinyl groups particularly preferable. Note that in formula(I), at least two R¹ groups are alkenyl groups, wherein the content ofthe alkenyl groups in terms of vinyl groups is not particularly limitedas long as the composition can be cured using the same. However, thecontent is preferably 2.0 mass % or less, more preferably 1.0 mass % orless, and further preferably 0.5 mass % or less. This is because, if thecontent of alkenyl groups is greater than necessary, when the releaselayer for a silicone adhesive is formed using the curable siliconecomposition according to the present invention as a release coatingagent, the release force of the release layer from the silicone adhesivelayer may be high. Note that the content in terms of vinyl groups refersto the content calculated by replacing the alkenyl groups other thanvinyl groups with the mass of an equimolar amount of vinyl groups.

Moreover, exemplary aryl groups in component (A) which may berepresented by R¹ in formula (I) having 6 to 12 carbon atoms includephenyl groups, tolyl groups, and xylyl groups, with phenyl groupspreferable.

Exemplary aralkyl groups which may be represented by R¹ in formula (I)having 7 to 12 carbon atoms include benzyl groups and phenethyl groups.

In formula (I), examples of the fluoro(poly)ether-containing organicgroup of R¹ include groups represented by the following formula (1).

F(CF₂O)_(a1)(CF₂CF₂O)_(a2)(CF₂CH₂O)_(a3)[CF(CF₃)CF₂O]_(a4)[CF(CF₃)CH₂O]_(a5)(CF₂CF₂CF₂O)_(a6)(CF₂CF₂CH₂O)_(a7)[CF(CF₃)]_(a8)(CF₂)_(a9)(CH₂)_(a10)—O—[CF(CF₃)]_(a11)(CF₂)_(a12)(CH₂)_(a13)—  Formula(I):

(wherein, a1 to a13 are integers of 0 or more. However, at least one ofa1 to a9 is an integer of 1 or more. The total of a1 to a10 ispreferably 21 or less, while the total of a11 to a13 is preferably 6 orless. Moreover, repeating units inCF₂O)_(a1)(CF₂CF₂O)_(a2)(CF₂CH₂O)_(a3)[CF(CF₃)CF₂O]_(a4)[CF(CF₃)CH₂O]_(a5)(CF₂CF₂CF₂O)_(a6)(CF₂CF₂CH₂O)_(a7)[CF(CF₃)]_(a8)(CF₂)_(a9)(CH₂)_(a10),as well as repeating units in [CH(CF₃)]_(a11)(CF₂)_(a12)(CH₂)_(a13) mayeach be randomly bonded.)

The fluoro(poly)ether-containing organic group of R¹ is furtherpreferably a group represented by any of the following formulas (2),(3), or (4).

F[CF(CF₃)CF₂O]_(b1)[CF(CF₃)CH₂O]_(b2)—[CF(CF₃)]_(b3)(CF₂)_(b4)(CH₂)_(b5)—  Formula(2):

(wherein, b1 to b5 are each an integer of 0 or more, b1+b2 is an integerof 1 or more, and b3+b4+b5 is an integer of 0 or more. b1+b2 ispreferably 21 or less, more preferably 11 or less, and furtherpreferably 6 or less. b3+b4+b5 is preferably 6 or less. Moreover,repeating units in [CF(CF₃)]_(b3)(CF₂)_(b4)(CH₂)_(b5) may each berandomly bonded.)

F(CF₂CF₂CF₂O)_(c1)(CF₂CF₂CH₂O)_(c2)—[CF(CF₃)]_(c3)(CF₂)_(c4)(CH₂)_(c5)—  Formula(3):

(wherein, c1 to c5 are integers of 0 or more, c1+c2 is an integer of 1or more, and c3+c4+c5 is an integer of 0 or more. c1+c2 is preferably 21or less, more preferably 11 or less, and further preferably 6 or less.c3+c4+c5 is preferably 6 or less Moreover, repeating units in(CF(CF₃))_(c3)(CF₂)_(c4)(CH₂)_(c5) may each be randomly bonded.)

F(CF₂)_(d1)(CH₂)_(d2)—O—(CH₂)_(d3)—  Formula (4):

(wherein, d1 and d2 are each an integer of 1 or more, while d3 is aninteger of 0 or more. d1 is preferably 10 or less, while d2 and d3 areeach preferably 6 or less.)

Particularly preferable fluoro(poly)ether-containing organic groupsinclude the following groups.

F[CF(CF₃)CF₂O]_(n)CF(CF₃)CF₂O(CH₂)₃—F[CF(CF₃)CF₂O]_(n)CF(CF₃)CH₂O(CH₂)₃—F[CF(CF₃)CF₂O]_(n+1)CF(CF₃)(CH₂)₂—F(CF₂)_(m)(CH₂)₂O(CH₂)₃—In each of the abovementioned formulas, I is preferably 1 to 20, morepreferably 1 to 10, and most preferably 1 to 5. Moreover, m ispreferably 1 to 6.

Moreover, a small amount of the fluoro(poly)ether-containing organicgroups may be bonded to the silicon atoms.

F[CF(CF₃)CF₂O]_(o)CF(CF₃)CF₂O—F[CF(CF₃)CF₂O]_(o)CF(CF₃)CH₂O—F(CF₂)_(p)(CH₂)₂O—In the abovementioned formulas, o is preferably 1 to 20, more preferably1 to 10, and most preferably 1 to 5. Moreover, p is preferably 1 to 6.

When the organopolysiloxane of formula (I) has two or morefluoro(poly)ether-containing organic groups per molecule, they may bethe same or different from each other.

Specific examples of component (A1) include, but are not limited to, thefollowing fluoro(poly)ether group-containing organopolysiloxanes. In thefollowing formulas, Me and Vi respectively represent methyl groups andvinyl groups, while F1a, F1b, F1c, F1d, and F1e respectively representthe groups indicated below.

F1a: CF₃CF₂CF₂O—CF(CF₃)CH₂O(CH₂)₃—F1b: F[CF(CF₃)CF₂O]₂CF(CF₃)CH₂O(CH₂)₃—F1c: F[CF(CF₃)CF₂O]₃CF(CF₃)CH₂O(CH₂)₃—F1d: F[CF(CF₃)CF₂O]₅CF(CF₃)CH₂O(CH₂)₃—F1e: F[CF(CF₃)CF₂O]₂CF(CF₃)CF₂O(CH₂)₃—an organopolysiloxane represented by the average composition formula:

(Me₂ViSiO_(1/2))₂(Me₂SiO_(2/2))₂₄₀(Me(F1a)SiO_(2/2))₁₂₀

an organopolysiloxane represented by the average composition formula:

(Me₂ViSiO_(1/2))₂(Me₂SiO_(2/2))₂₄₅(Me(F1b)SiO_(2/2))₁₂₀

an organopolysiloxane represented by the average composition formula:

(Me₂ViSiO_(1/2))₂(Me₂SiO_(2/2))₂₄₀(Me(F1b)SiO_(2/2))₁₂₀(MeViSiO_(2/2))₃

an organopolysiloxane represented by the average composition formula:

(Me₃SiO_(1/2))₂(Me₂SiO_(2/2))₂₄₀(Me(F1b)SiO_(2/2))₁₂₀(MeViSiO_(2/2))₆

an organopolysiloxane represented by the average composition formula:

(Me₂ViSiO_(1/2))₂(Me₂SiO_(2/2))₆₆₀(Me(F1b)SiO_(2/2))₃₃₀(MeViSiO_(2/2))₆

an organopolysiloxane represented by the average composition formula:

(Me₂ViSiO_(1/2))₂(Me₂SiO_(2/2))₃₀₀(Me(F1c)SiO_(2/2))₁₀₀(MeViSiO_(2/2))₃

an organopolysiloxane represented by the average composition formula:

(Me₂ViSiO_(1/2))₂(Me₂SiO_(2/2))₂₄₀(Me(F1d)SiO_(2/2))₁₂₀(MeViSiO_(2/2))₃

an organopolysiloxane represented by the average composition formula:

(Me₂ViSiO_(1/2))₂(Me₂SiO_(2/2))₂₄₅(Me(F1e)SiO_(2/2))₁₂₀

These polysiloxanes can be manufactured by conventionally well-knownmethods. For example, a dichlorosilane having a fluoro(poly)ether groupcan be manufactured by the method proposed in JP H4-28273 B, abis(hydridesiloxy)silane having a fluoro(poly)ether group can bemanufactured by substituting chlorine atoms of a dichlorosilane with adimethylsiloxy group using the method proposed in JP H3-197484 A, acyclotrisiloxane substituted with a fluoro(poly)ether group can bemanufactured by dehydrocondensation in a molecule using the methodproposed in JP H6-321968 A, and this can be manufactured by equilibriumpolymerization with a vinyl group-containing siloxane in the mannerdisclosed in JP S64-74268 A or by non-equilibrium polymerization via themethod proposed in JP H11-246772 A.

Moreover, after the alkenyl-functional fluoro(poly)ether-modifiedorganopolysiloxane used as component (A1) of the present invention ismanufactured by subjecting a fluoro(poly)ether group-containing alkenylether having a stoichiometric amount or less to a hydrosilylationreaction with respect to the silicon atom-bonded hydrogenatom-containing polysiloxane to introduce a fluoro(poly)ether group, alarge excess of acetylene or terminal dienes such as 1,5-hexadiene and1,3-butadiene is subjected to a hydrosilylation reaction with respect tounreacted residual silicon atom-bonded hydrogen atoms, with thefollowing polysiloxanes capable of being exemplified.

While not limited thereto, specific examples of component (A1)manufactured by the present method include the followingfluoro(poly)ether group-containing organopolysiloxanes. In the followingformulas, Me, Vi, and Hex respectively represent methyl groups, vinylgroups, and n-hexenyl groups, while F1b, F1f, and F1g respectivelyrepresent the groups indicated below.

F1b: F[CF(CF₃)CF₂O]₂CF(CF₃)CH₂O(CH₂)₃—

F1f: F[CF(CF₃)CF₂O]₃CF(CF₃)CH₂O(CH₂)₃—,and F[CF(CF₃)CF₂O]₄CF(CF₃)CH₂O(CH₂)₃—are contained at a molar ratio of 1:1F1g: F[CF(CF₃)CF₂O]₁₀CF(CF₃)CH₂O(CH₂)₃—an organopolysiloxane represented by the average composition formula:

(Me₃SiO_(1/2))₂(Me₂SiO_(2/2))₂₀₀(Me(F1b)SiO_(2/2))₁₀₀(MeHexSiO_(2/2))₄

an organopolysiloxane represented by the average composition formula:

(Me₃SiO_(1/2))₂(Me₂SiO_(2/2))₂₅₀(Me(F1f)SiO_(2/2))₁₁₀(MeHexSiO_(2/2))₄

an organopolysiloxane represented by the average composition formula:

(Me₃SiO_(1/2))₂(Me₂SiO_(2/2))₁₉₀(Me(F1g)SiO_(2/2))₃₀(MeHexSiO_(2/2))₂

an organopolysiloxane represented by the average composition formula:

(Me₃SiO_(1/2))₂(Me₂SiO_(2/2))₂₃₀(Me(F1g)SiO_(2/2))₃₅(MeHexSiO_(2/2))₄

Note that the content of fluorine atoms per molecule usingfluoro(poly)ether-containing organic groups is preferably no less than30 mass %, more preferably no less than 35 mass %, and furtherpreferably 40 mass %. This is because when the content of fluorine atomsin component (A1) is 30 mass % or more, a releasable film obtained bycrosslinking the present curable silicone composition exhibits goodpeeling force with respect to a silicone pressure-sensitive adhesive.Note that the upper limit of the content of fluorine atoms in component(A1) is not particularly limited; however, when the content is too high,component (A1) itself tends to have lower solubility in the solvent,which impairs the handleability, so the content is preferably at most 60mass % or at most 55 mass %.

Moreover, an example of component (A2) is an organopolysiloxanerepresented by the average composition formula (II):

(R² ₃SiO_(1/2))_(w)(R²₂SiO_(2/2))_(x)(R²SiO_(3/2))_(y)(SiO_(4/2))_(z)  (II)

(wherein, the R² moieties are the same or different alkyl groups having1 to 12 carbon atoms, alkenyl groups having 2 to 12 carbon atoms, arylgroups having 6 to 12 carbon atoms, aralkyl groups having 7 to 12 carbonatoms, or fluoroalkyl groups having 1 to 12 carbon atoms; and in eachmolecule, at least two R² moieties are alkenyl groups and at least oneR² moiety is a fluoroalkyl group having 1 to 12 carbon atoms, w is apositive number, x is a positive number, y is 0 or a positive number,and z is 0 or a positive number).

Regarding w to z in the abovementioned formula (II), w is an integer of2 or more, preferably an integer of 2 to 6, x is an integer of 1 ormore, preferably an integer of 1 to 5,000, more preferably an integer of30 to 4,000, y is 0 or a positive number, and z is 0 or a positivenumber. When the degree of siloxane polymerization is less than thelower limit of the range described above, when the curable siliconecomposition obtained using this component is used as a release coatingagent, formation of the release layer may be difficult, while when thedegree of siloxane polymerization exceeds the upper limit of the rangedescribed above, the coating properties (particularly thin filmapplicability) of the obtained curable silicone composition maydecrease.

The alkyl, alkenyl, aryl, and aralkyl groups of R² may be exemplified bygroups similar to those listed as R¹.

Exemplary fluoroalkyl groups of R² include 3,3,3-trifluoropropyl groups,3,3,4,4,4-pentafluorobutyl groups, 3,3,4,4,5,5,5-heptafluoropentylgroups, 3,3,4,4,5,5,6,6,6-nonafluorohexyl groups,3,3,4,4,5,5,6,6,7,7,7-undecafluoroheptyl groups,3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl groups, and3,3,4,4,5,5,6,6,7,7,8,8,9,9,9-pentadecafluorononyl groups, wherein3,3,4,4,5,5,5-heptafluoropentyl groups,3,3,4,4,5,5,6,6,6-nonafluorohexyl groups,3,3,4,4,5,5,6,6,7,7,7-undecafluoroheptyl groups, or3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl groups are preferable.

Examples of such component (A2) include the followingorganopolysiloxanes. Note that in the following formulas, Me, Vi, Hex,F2a, F2b, and F2c respectively represent a methyl group, a vinyl group,an n-hexenyl group, along with a 3,3,4,4,5,5,6,6,6-nonafluorohexylgroup, a 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluoro octyl group, and a3,3,3-trifluoro propyl group. an organopolysiloxane represented by theaverage composition formula:

(Me₂ViSiO_(1/2))₂(Me₂SiO_(2/2))₇₅₀(Me(F2a)SiO_(2/2))₇₅₀(MeViSiO_(2/2))₂₀

an organopolysiloxane represented by the average composition formula:

(Me₃SiO_(1/2))₂(Me₂SiO_(2/2))₄₅₀(Me(F2a)SiO_(2/2))₃₅₀(MeViSiO_(2/2))₁₀

an organopolysiloxane represented by the average composition formula:

(Me₂(Fa1)SiO_(1/2))₂(Me₂SiO_(2/2))₄₅₀(Me(F2a)SiO_(2/2))₃₅₀(MeViSiO_(2/2))₁₀

an organopolysiloxane represented by the average composition formula:

(Me₂HexSiO_(1/2))₂(Me₂SiO_(2/2))₁₀₀₀(Me(F2a)SiO_(2/2))₁₀₀₀(MeHexSiO_(2/2))₂₀

an organopolysiloxane represented by the average composition formula:

(Me₂ViSiO_(1/2))₄(Me₂SiO_(2/2))₅₀₀(Me(F2a)SiO_(2/2))₅₀₀(SiO_(4/2))₁

an organopolysiloxane represented by the average composition formula:

(Me₂ViSiO_(1/2))₂(Me₂SiO_(2/2))₉₀₀(Me(F2b)SiO_(2/2))₄₅₀(MeViSiO_(2/2))₁₀

an organopolysiloxane represented by the average composition formula:

(Me₂ViSiO_(1/2))₂(Me₂SiO_(2/2))₁₄₅₀(Me(F2a)SiO_(2/2))₁₁₀₀(MeViSiO_(2/2))₅

an organopolysiloxane represented by the average composition formula:

(Me₂ViSiO_(1/2))₂(Me₂SiO_(2/2))₁₂₅₀(Me(F2a)SiO_(2/2))₁₂₅₀(MeViSiO_(2/2))₇

an organopolysiloxane represented by the average composition formula:

(Me₂ViSiO_(1/2))₂(Me₂SiO_(2/2))₉₀₀(Me(F2a)SiO_(2/2))₄₅₀(MeViSiO_(2/2))₁₀

an organopolysiloxane represented by the average composition formula:

(Me₂ViSiO_(1/2))₂(Me₂SiO_(2/2))₁₁₀₀(Me(F2a)SiO_(2/2))₄₀₀(MeViSiO_(2/2))₇

an organopolysiloxane represented by the average composition formula:

(Me₂ViSiO_(1/2))₂(Me₂SiO_(2/2))₁₁₀₀(Me(F2a)SiO_(2/2))₄₀₀(Me(F2c)SiO_(2/2))₁₀₀(MeViSiO_(2/2))₁₀

One or more selected from these can be combined and used.

Note that the content of fluorine atoms per molecule usingfluoroalkyl-containing organic groups is preferably no less than 30 mass%, more preferably no less than 35 mass %, and further preferably 40mass %. This is because when the content of fluorine atoms in component(A2) is 30 mass %, a releasable film obtained by crosslinking thepresent curable silicone composition exhibits good peeling force withrespect to a silicone pressure-sensitive adhesive. Note that the upperlimit of the content of fluorine atoms in component (A2) is notparticularly limited; however, when the content is too high, component(A2) itself tends to have lower solubility in the solvent, which impairsthe handleability, so the content therefore is preferably at most 60mass % or at most 55 mass %.

The component (A1) and the component (A2) are preferably a combinationof those which are not completely compatible at 25° C. when mixed in asolventless manner. The phrase of “not completely compatible at 25° C.when mixed in a solventless manner” means that when the mixture of twoor more fluorine-containing organopolysiloxanes is placed in atransparent glass vial with a lid at a mass ratio of 1:1, thensufficiently stirred at 25° C., and immediately thereafter visuallyobserved after 24 hours to be cloudy or be separated into two phaseswithout exhibiting a uniform and transparent liquid state. Note thatthis means that when the fluorine-containing organopolysiloxanes isother than a gum-like or paste-like liquid at 25° C., the mixture isheated to a temperature in liquid form, sufficiently stirred and thencooled to 25° C., and immediately thereafter visually observed after 24hours to be cloudy or to be separated into two phases without exhibitinga uniform and transparent liquid state.

Moreover, component (A2) can use a single fluoroalkyl group-containingorganopolysiloxane, or a mixture of two or more fluoroalkylgroup-containing organopolysiloxanes with different average compositionformulas. In this case, the two or more organopolysiloxane-containingfluoroalkyl groups may or may not be compatible with each other at 25°C. when mixed in a solventless manner.

[Component (B)]

Component (B) is an organopolysiloxane having at least three siliconatom-bonded hydrogen atoms (Si—H) per molecule and is a component forcuring the composition according to an embodiment of the presentinvention by carrying out an addition reaction using a hydrosilylationreaction with component (A).

Examples of groups bonded to silicon atoms in component (B) other thanhydrogen atoms include alkyl groups having 1 to 12 carbon atoms, arylgroups having 6 to 12 carbon atoms, aralkyl groups having 7 to 12 carbonatoms, and fluoroalkyl groups having 1 to 12 carbon atoms, andfluoro(poly)ether-containing organic groups having 2 to 100 carbonatoms. Note that a small amount of hydroxyl groups or alkoxy groups maybe bonded to the silicon atoms in component (B) within a range that doesnot impair the object of the present invention.

The molecular structure of component (B) is not limited. Examplesthereof include a straight-chain structure, a branched-chain structure,a partially branched straight-chain structure, a resinous structure, anda cyclic structure, with a straight-chain structure or a partiallybranched straight-chain structure being preferable.

An example of such component (B) is an organopolysiloxane represented bythe following average unit formula (III):

(R³ ₃SiO_(1/2))_(aa)(R³₂SiO_(2/2))_(ab)(R³SiO_(3/2))_(ac)(SiO_(4/2))_(ad)  (III).

In formula (III), the R³ moieties are the same or different and areindependently hydrogen atoms, alkyl groups having from 1 to 12 carbonatoms, aryl groups having 6 to 12 carbon atoms, aralkyl groups havingfrom 7 to 12 carbon atoms, fluoroalkyl groups having 1 to 12 carbonatoms, or fluoro(poly)ether-containing organic groups, provided that atleast three of the R³ moieties are hydrogen atoms. Moreover, aa is apositive number, ab is a positive number, ac is 0 or a positive number,and ad is 0 or a positive number. However, when aa is 2, the total of aato ad is preferably within a range of from to 200, and is within a givencombination range of upper limits and lower limits with a lower limit of10 or 15 and an upper limit of 150, 120, 100, 80, 70, 60, 50, or 40.This is because when aa is 2 and the total of aa to ad is greater thanor equal to the lower limit of the range described above, crosslinkingof the present composition progresses sufficiently, while when the totalis less than or equal to the upper limit of the range described above,the handleability of the present composition is favorable.

Exemplary alkyl groups having 1 to 12 carbon atoms which may berepresented by R³ include methyl groups, ethyl groups, propyl groups,butyl groups, pentyl groups, hexyl groups, heptyl groups, octyl groups,nonyl groups, decyl groups, undecyl groups, and dodecyl groups, withmethyl groups preferable.

Moreover, exemplary aryl groups having 6 to 12 carbon atoms which may berepresented by R³ include phenyl groups, tolyl groups, and xylyl groups,with phenyl groups preferable.

Moreover, exemplary aralkyl groups having 7 to 12 carbon atoms which maybe represented by R³ include benzyl groups and phenethyl groups.

Further, the fluoroalkyl group having 1 to 12 carbon atoms which may berepresented by R³ is not particularly limited, with a fluoroalkyl groupindicated by R² preferably used.

Moreover, as the fluoro(poly)ether-containing organic groups which maybe represented by R³, the fluoro(poly)ether-containing organic groupsillustrated in the abovementioned R¹ are preferably used.

Component (B) according to the present invention may or may not have agroup selected from fluoroalkyl groups and fluoro(poly)ether-containingorganic groups. Even when an organohydrogenpolysiloxane having afluorine atom-containing group is not used as component (B), when thepresent composition is combined with the abovementioned (A) and curedusing the composition as a coating agent, a release layer havingexcellent releasability, particularly excellent releasability withrespect to the silicone adhesive, is obtained when the compositionaccording to the present invention is cured using the composition as acoating agent. Component (B) is particularly preferably anorganohydrogenpolysiloxane represented by the abovementioned averagecomposition formula (III), and R³ is a combination of a hydrogen atom,an alkyl group (specifically, a methyl group), a fluoroalkyl group,and/or a fluoro(poly)ether-containing organic group.

When component (B) according to the present invention has a groupselected from the group consisting of fluoroalkyl groups andfluoro(poly)ether-containing organic groups, the fluorine atom contentderived from fluoroalkyl groups and/or fluoro(poly)ether-containingorganic groups per molecule is not particularly limited, but ispreferably at least mass %, at least 25 mass %, at least 30 mass %, orat least 35 mass %. Moreover, the upper limit of the fluorine atomcontent in component (B) is preferably at most 60 mass % or at most 50mass %.

Specific examples of component (B) include, but are not limited to, theorganopolysiloxanes listed below. In the following formulas, Me, F2a,and F1b respectively represent a methyl group, a3,3,4,4,5,5,6,6,6-nonafluorohexyl group, and a group represented by thefollowing formula:

F[CF(CF₃)CF₂O]₂CF(CF₃)CH₂O—(CH₂)₃—

an organopolysiloxane represented by the average composition formula:

(Me₃SiO_(1/2))₂(Me(F2a)SiO_(2/2))₁₂(MeHSiO_(2/2))₂₇

an organopolysiloxane represented by the average composition formula:

(Me₃SiO_(1/2))₂(Me₂SiO_(2/2))₅₅(Me(F1b)SiO_(2/2))₂₅(MeHSiO_(2/2))₂₅

an organopolysiloxane represented by the average composition formula:

(Me₃SiO_(1/2))₂(MeHSiO_(2/2))₅₀

an organopolysiloxane represented by the average composition formula:

(Me₃SiO_(1/2))₂(Me₂SiO_(2/2))₃₀(MeHSiO_(2/2))₃₀

an organopolysiloxane represented by the average composition formula:

(Me₂HSiO_(1/2))₂(Me₂SiO_(2/2))₃₀(MeHSiO_(2/2))₃₀

One or more selected from these can be combined and used as component(B).

The content of component (B) in the curable silicone compositionaccording to the present invention is an amount such that the molarratio of the silicon-bonded hydrogen atoms to the alkenyl groups incomponent (A) is within a range of 0.1 to 20 (silicon atom-bondedhydrogen atoms/alkenyl groups), and is preferably within a givencombination range of upper limits and lower limits with a lower limit of0.5, 0.8, or 1 and an upper limit of 18, 17, 16, 15, 14, 13, or 12. Thisis because when the content of component (B) is greater than or equal tothe lower limit of the range described above, crosslinking of thepresent curable silicone composition progresses sufficiently, while whenthe content is less than or equal to the upper limit of the rangedescribed above, the characteristics of the resulting releasable filmmay be stabilized.

[Component (C)]

Component (C) is a hydrosilylation reaction catalyst for promotingcuring with the hydrosilylation reaction of the curable siliconecomposition. Examples thereof include platinum-based catalysts,rhodium-based catalysts, and palladium-based catalysts, withplatinum-based catalysts being preferable. Examples of platinum-basedcatalysts include platinum fine powder, platinum black, platinumsupporting silica fine powder, platinum supporting activated carbon,chloroplatinic acid, alcohol solutions of chloroplatinic acid, olefincomplexes of platinum, and alkenylsiloxane complexes of platinum.

The content of component (C) is an amount that promotes curing of thepresent curable silicone composition and is specifically an amount inwhich the metal atoms, preferably platinum atoms, in the catalyst arewithin a range of 0.1 to 1,000 ppm in mass units with respect to thepresent curable silicone composition. This is because, when the amountof component (C) is greater than or equal to the lower limit of therange described above, curing of the resulting curable siliconecomposition progresses, while when the amount is less than or equal tothe upper limit of the range described above, the resulting curedproduct becomes less susceptible to discoloration.

[Component (D)]

Component (D) is any organic solvent capable of compatibilizing theentire composition while uniformly compatibilizing thefluorine-containing organopolysiloxane mixture serving as component (A).Here, “compatibilizing” means that turbidity is not observed in theappearance at 25° C. and a uniform and transparent liquid is provided.

Moreover, by adding an organic solvent, the viscosity of the curablesilicone composition can be reduced, improving the applicationworkability and wettability to the substrate.

Component (D), which is preferably a solvent mixture, consists of onesolvent or two or more solvents selected from the group consisting ofdiethyl ether, dipropyl ether, diisopropyl ether, dibutyl ether,diisobutyl ether, di-sec-butyl ether, di-tert-butyl ether,methyl-tert-butyl ether, ethyl-tert-butyl ether, pentane, m-xylenehexafluoride, methylheptafluoropropyl ether, methylnonafluorobutylether, ethylnonafluorobutyl ether, and3-methoxy-1,1,1,2,2,3,4,4,5,5,6,6,6-tridecafluoro hexane.

Other organic solvents may be further used in addition to theabovementioned organic solvent, provided that the appearance of thecurable silicone composition can be maintained transparent and uniformat 25° C. from the preparation of the composition until the use thereof.While not particularly limited thereto, exemplary such additionalorganic solvents include: hydrocarbon-based solvents such as aromatichydrocarbon-based solvents such as toluene and xylene, aliphatichydrocarbon-based solvents such as hexane, heptane, octane, isooctane,decane, cyclohexane, methylcyclohexane, and isoparaffin, industrialgasoline (rubber solvents or the like), petroleum benzene, and solventnaphtha; ketone-based solvents such as acetone, methyl ethyl ketone,2-pentanone, 3-pentanone, 2-hexanone, 2-heptanone, 4-heptanone, methylisobutyl ketone, diisobutyl ketone, acetonyl acetone, and cyclohexanone;ester-based solvents such as ethyl acetate, propyl acetate, isopropylacetate, butyl acetate, and isobutyl acetate; solvents having ester andether components such as 2-methoxyethylacetate, 2-ethoxyethylacetate,propylene glycol monoether acetate, and 2-butoxyethylacetate;siloxane-based solvents such as hexamethyl disiloxane, octamethyltrisiloxane, octamethyl cyclotetrasiloxane, decamethylcyclopentasiloxane, tris(trimethylsiloxy)methylsilane, andtetrakis(trimethylsiloxy)silane; fluorine modified solvents other thansaid m-xylene hexafluoride, methylheptafluoropropyl ether,methylnonafluorobutyl ether, ethylnonafluorobutyl ether, and3-methoxy-1,1,1,2,2,3,4,4,5,5,6,6,6-tridecafluorohexane, for example,fluorine modified aromatic hydrocarbon based solvents such asbenzotrifluoride; fluorine modified ether based solvents such asperfluoro(2-butyltetrahydrofuran); fluorine modified alkylamine basedsolvents such as perfluorotributylamine and perfluorotripentylamine; andmixed solvents of two or more types selected therefrom.

The content of component (D) is an amount necessary to uniformlycompatibilize the entire curable silicone composition and is 10,000parts by mass or less per 100 parts by mass of component (A), preferablywithin a range of 20 to 5,000 parts by mass.

Component (E)

The present curable silicone composition may also contain (E) ahydrosilylation reaction inhibitor in order to control the crosslinkingreactions thereof. Examples of component (E) include: alkyne alcoholssuch as 1-ethynylcyclohexane-1-ol, 2-methyl-3-butyne-2-ol,3,5-dimethyl-1-hexyne-3-ol, and 2-phenyl-3-butyne-2-ol; enyne compoundssuch as 3-methyl-3-pentene-1-yne and 3,5-dimethyl-3-hexene-1-yne; methylalkenyl siloxane oligomers such as1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane and1,3,5,7-tetramethyl-1,3,5,7-tetrahexenylcyclotetrasiloxane;alkyneoxysilanes such as dimethyl bis(3-methyl-1-butyne-3-oxy)silane andmethylvinyl bis(3-methyl-1-butyne-3-oxy)silane; alkyneoxysilanecompounds such as methyltris(1-methyl-1-phenyl-propyneoxy)silane,dimethylbis(1-methyl-1-phenyl-propyneoxy)silane,methyltris(1,1-dimethyl-propyneoxy)silane,dimethylbis(1,1-dimethyl-propyneoxy)silane; and benzotriazoles.

The content of component (E) is not limited and in terms of impartingsufficient pot-life to the present curable silicone composition, thecontent of component (E) upon use thereof is preferably within a rangeof from 0.01 to 5 parts by mass, within a range of from 0.05 to 5 partsby mass, or within a range of from 0.05 to 3 parts by mass with respectto 100 parts by mass of component (A).

[Other Additives]

The present curable silicone composition may use an additive selectedfrom a photopolymerization initiator, an antioxidant, a reactivediluent, a leveling agent, a filler, an antistatic agent, an antifoamingagent, a pigment, etc. as long as it can achieve the object of thepresent invention.

[Application]

The curable silicone composition according to the present invention ispreferably used as a release coating agent and is suitable for use as arelease coating agent for an adhesive. In particular, it is mostsuitable for use as a release coating agent for silicone adhesives.

The present invention also relates to a release film including: asubstrate, in particular, a film-like substrate; and a release layerconsisting of a cured product obtained by curing the release coatingagent according to the present invention. Such a release film can bemanufactured by, for example, applying the curable silicone compositionaccording to the present invention to a film-like substrate and curingthe curable silicone composition. The release film according to thepresent invention is particularly suitable for use as a siliconeadhesive.

A film-like substrate selected from a paper or plastic film, glass,metal, etc. can be used as the substrate employed for the release film.Examples of paper include high-quality paper, coated paper, art paper,glassine paper, polyethylene laminate paper, and craft paper. Examplesof plastic films include polyethylene films, polypropylene films,polyester films, polyimide films, polyvinyl chloride films,polyvinylidene chloride films, polyvinyl alcohol films, polycarbonatefilms, polytetrafluoroethylene films, polystyrene films, ethylene-vinylacetate copolymer films, ethylene-vinyl alcohol copolymer films,triacetyl cellulose films, polyether ether ketone films, andpolyphenylene sulfide films. The substrate on which the release layer isprovided does not need to be a film-like substrate, with a substrate ofany shape capable of being used. When the glass, for example, asheet-like glass, is used as the substrate, the glass is notparticularly limited in terms of thickness, type, or the like, and maybe subjected to chemical reinforcement treatment or the like. Inaddition, glass fibers may also be used as substrates and may be usedalone or in combination with another resin. Exemplary metal substratesinclude aluminum foil, copper foil, gold foil, silver foil, and nickelfoil. If a product provided on the substrate is used as a release film,the substrate is preferably a plastic film, more preferably a polyesterfilm. In particular, both the substrate and the release layer arepreferably optically transparent.

The thickness of the release layer is preferably 2.0 μm or less, 1.0 μmor less, or 0.5 μm or less, more preferably 0.4 μm or less, and furtherpreferably 0.3 μm or less. Moreover, the thickness is preferably 0.05 μmor more, more preferably 0.1 μm or more. This is because, if the filmthickness is at the lower limit or higher of the abovementioned range,the release force of the obtained release layer is sufficiently low; incontrast, if the film thickness is at the upper limit or lower of theabovementioned range, the light transmittance of the release layer isparticularly excellent.

[Laminate]

The present invention also relates to a laminate which is configured toinclude at least: a release layer consisting of a cured product obtainedby curing the curable silicone composition according to the presentinvention; and an adhesive layer disposed so as to face the releaselayer, in particular a silicone adhesive layer. In this case, thecurable silicone composition can be a release coating agent. In thiscase, the meaning of “facing” means that the release layer and theadhesive layer are in direct contact. Therefore, in the presentinvention, the release layer and the adhesive layer are generallydisposed so as to face each other. In the following description, while asilicone adhesive agent is used as an example to describe theconfiguration of the laminate according to the present invention, theadhesive agent is not limited to the silicone adhesive.

The laminate according to the present invention may be a laminate havingany structure as long as the release layer and the silicone adhesivelayer are disposed so as to face each other. Specific examples oflaminates are described below.

Examples of the configuration of the laminate according to the presentinvention include the following (a) to (d).

(a) a configuration consisting of a first substrate/releaselayer/silicone adhesive layer/second substrate;(b) a configuration formed by continuously laminating two or moreconfiguration units consisting of a substrate/release layer/siliconeadhesive layer;(c) a configuration consisting of a first substrate/first releaselayer/silicone adhesive layer/second release layer/second substrate; and(d) a configuration formed by continuously laminating two or moreconfiguration units consisting of a substrate/first releaselayer/silicone adhesive layer/second release layer. In configurations(b) and (d), the substrate may be discontinuous or continuous; wherein,in general, if the substrate is discontinuous, the laminate is formedinto a sheet shape, while when a continuous material is used, thelaminate is rolled.

The configurations (a) to (d) of the laminate will be described infurther detail.

<Regarding Configuration (a)>

The laminate of configuration (a) has a configuration including a firstsubstrate, a release layer disposed on the first substrate, a siliconeadhesive layer disposed on the release layer, and a second substratedisposed on the silicone adhesive layer, wherein the release layerconsists of a cured product formed by curing the release coating agentaccording to the present invention. The laminate of configuration (a)can be part of a laminate which includes not only the laminate itself,but also the configuration thereof. A schematic view of an example ofconfiguration (a) is illustrated in FIG. 1.

<Regarding Configuration (b)>

The laminate of configuration (b) has a configuration formed bycontinuously laminating two or more configuration units consisting of afirst substrate, a first release layer disposed on the first substrate,and a silicone adhesive layer disposed on the first release layer,wherein the release layer consists of a cured product formed by curingthe release coating agent according to the present invention. Further, anew substrate is preferably disposed on the silicone adhesive layerdisposed on the outermost layer of the configuration. The laminate ofconfiguration (b) can be part of a laminate which includes not onlylaminate itself, but also the configuration thereof. FIG. 2 illustratesa schematic view of one example of configuration (b). In FIG. 2, thereare two of the abovementioned successive configuration units, wherein anew substrate is disposed on the silicone adhesive layer disposed on theoutermost layer of the configuration. However, configuration (b) is notlimited to the aspect illustrated in FIG. 2.

<Regarding Configuration (c)>

The laminate of configuration (c) has a configuration including a firstsubstrate, a first release layer disposed on the first substrate, asilicone adhesive layer disposed on the first release layer, a secondrelease layer disposed on the silicone adhesive layer, and a secondsubstrate disposed on the second release layer, wherein one or both ofthe first release layer and the first release layer consist(s) of acured product formed by curing the release coating agent according tothe present invention. The laminate of configuration (c) can be part ofa laminate which includes not only laminate itself, but also theconfiguration thereof. A schematic view of one example of configuration(c) is illustrated in FIG. 3.

<Regarding Configuration (d)>

The laminate of configuration (d) has a configuration formed bycontinuously laminating two or more configuration units consisting of afirst substrate, a first release layer disposed on the first substrate,a silicone adhesive layer disposed on the first release layer, and asecond release layer disposed on the silicone adhesive layer, whereinone or both of the first release layer and the second release layerconsist(s) of a cured product formed by curing the release coating agentaccording to the present invention. Further, a new substrate ispreferably disposed on the release layer disposed on the outermost layerof the configuration. The laminate of configuration (d) can be part of alaminate which includes not only laminate itself, but also theconfiguration thereof. FIG. 4 illustrates a schematic view of oneexample of configuration (d). In FIG. 4, there are two of theabovementioned successive configuration units, wherein a new substrateis disposed on the release layer disposed on the outermost layer of theconfiguration. However, configuration (b) is not limited to the aspectillustrated in FIG. 4.

In configurations (b) and (d) of the abovementioned laminate, if thesubstrate is discontinuous (sheet shaped), all of the substrate, therelease layer, and the silicone adhesive layer may be the same ordifferent from each other, including in terms of types and thicknesses.Moreover, when the substrate is continuous (roll shaped), the substrate,the silicone adhesive layer, and the one or two release layers are eachidentical.

Such a substrate is preferably sheet-like or film-like and isparticularly preferably a film-like substrate, with a substrate similarto the substrate used in the release film capable of being used.

Moreover, such a substrate which is light transmissive or lightnon-transmissive may be used, and if multiple substrates are used, bothlight transmissive and light non-transmissive ones may be optionallycombined depending on the purpose.

The laminate according to the present invention preferably has a rollshape, for example, a roll shape wound on an appropriate cylindrical ortubular core.

In the laminate of the present invention, the configuration (forexample, corresponding to configuration (c) or (d)) is a configurationin which a first release layer is disposed so as to face one surface ofboth surfaces with respect to the silicone adhesive layer, and a secondrelease layer is disposed so as to face the other surface, wherein atleast one of the first release layer and the second release layer mustbe a release layer consisting of a cured product formed by curing therelease coating agent according to the present invention, and wherein arelease force (F1) upon releasing the silicone adhesive from the firstrelease layer preferably differs from a release force (F2) uponreleasing the silicone adhesive from the second release layer.

When the difference in the release force between F1 and F2 is small,after the operation of releasing one of the release layers from thesilicone adhesive layer (releasing the first facing surface), uponreleasing the first opposing surface in the operation of releasing theother release layer (second facing surface), the second facing surfacemay be unintentionally released, as a result of which the siliconeadhesive layer may be broken, making it difficult to be used as theoriginally intended adhesive. The release force difference is preferably10 gf/inch or more, more preferably 20 gf/inch or more.

Examples of the method for achieving the abovementioned release forcedifference include a method for selecting a method for forming thefacing surfaces as described below, a method for making two types ofrelease layers different, etc.

In the laminate according to the present invention, the thickness of therelease layer is independently 2.0 μm, 1.0 μm, or 0.5 μm or less, morepreferably 0.4 μm or less, and further preferably 0.3 μm or less.Moreover, the thickness is preferably 0.05 μm or more, more preferably0.1 μm or more. This is because, if the film thickness of the releaselayer is at the lower limit or higher of the abovementioned range, therelease force of the release layer from the silicone adhesive issufficiently low; in contrast, if the film thickness is at the upperlimit or lower of the abovementioned range, the light transmittance ofthe release layer is particularly excellent and the economics thereofare also excellent.

The silicone adhesive composition or the curable silicone adhesivecomposition which can be used in the laminate according to the presentinvention is not limited to a specific substance, with those thatconform to any desired laminate application, for example, anyapplication as an adhesive tape capable of being used; however, anadhesive having a relatively high adhesive force is preferably used.

The curing mechanism of the curable silicone adhesive is notparticularly limited, with hydrosilylation curability, peroxidecurability, photocuring, etc. used. However, curing at a relatively lowtemperature can be carried out and the effects of heat on the substrateand the application material can be reduced, with hydrosilylation curingproperties having excellent economics including ease of step preferablyused.

A commercially available composition may be used as the siliconepressure-sensitive adhesive composition. As such a siliconepressure-sensitive adhesive, hydrosilylation curable SD 4580 PSA, SD4584 PSA, and SD 4585 PSA, etc. manufactured by Dow Corning Toray Co.,Ltd. can be used. Moreover, a silicone adhesive agent which has largeelongation at break is preferably used with the storage modulus at lowtemperatures kept lower wherein, in assembling applications,particularly OCA applications, high adhesion and high flexibility may berequired in a wider temperature range including low temperatures, suchthat the glass transition temperature of the cured adhesive compositionis low; for example, the composition can be designed to be roomtemperature or lower. Examples thereof include silicone adhesivecompositions proposed by the present applicant in WO 2017/188308, etc.

While not particularly limited thereto, the thickness of the siliconeadhesive layer of the laminate according to the present invention ispreferably 0.1 to 300 μm, more preferably 0.5 to 200 μm.

Moreover, in the laminate according to the present invention, thesilicone adhesive layer can be formed on the entire surface of the layeror on only a portion of the surface thereof. Although no particularlimitations are placed on aspects in which the silicone adhesive layeris formed only on a portion of the surface, silicone adhesive agents maybe applied so as to form any shape such as one or more points, one ormore straight lines or curved lines, and concentric circles. While therelease layer may be formed on the entire surface configuring therelease layer, the release layer may also be formed in accordance withthe shape of the silicone adhesive formed on the silicone adhesivelayer.

[Manufacturing Method of Laminate]

While the method for manufacturing the laminate according to the presentinvention is not particularly limited, some preferable methods arelisted below. First, the following two methods are exemplified asmethods for preparing the facing surfaces of the silicone adhesive layerand the release layer in manufacturing the laminate according to thepresent invention.

<Method (1) for Preparing the Facing Surfaces of the Silicone AdhesiveLayer and the Release Layer>

The first method for preparing the facing surface includes:Step (1) involving forming a first release film including a firstrelease layer by applying and curing a release coating agent consistingof the curable silicone composition according to the present inventionon a film-like substrate;Step (2) involving forming a silicone adhesive layer by applying andcuring a curable silicone adhesive composition on a film-like substratethat is the same as the film-like substrate or a second film-likesubstrate that is different from the film-like substrate; andStep (3) involving adhering together the release layer of the firstrelease film obtained by the aforementioned step (1) on the siliconeadhesive layer obtained by step (2).The preparation method is a method in which a previously cured releaselayer and a previously cured silicone adhesive layer are brought intocontact with each other to form facing surfaces of both layers.

<Method (2) for Preparing the Facing Surfaces of the Silicone AdhesiveLayer and the Release Layer>

The second method for preparing the facing surface includes:Step (1) involving forming a first release film including a firstrelease layer by applying and curing a release coating agent consistingof the curable silicone composition according to the present inventionon a film-like substrate;Step (2) involving forming a silicone adhesive layer by applying andcuring a curable silicone adhesive composition on the first release filmobtained by step (1); andStep (3) involving adhering together a film-like substrate that is thesame as or different from the film substrate on the silicone adhesivelayer obtained by step (2).The preparation method is a method in which a curable silicone adhesiveis applied and cured on a previously cured release layer to form facingsurfaces of both layers. In general, compared to the first method, thesecond method often has a high release force difference between thesilicone adhesive and the release agent.

Next, the manufacturing methods are exemplified for configurationexamples (a) to (d) of the abovementioned laminate according to thepresent invention. Of these, the facing surfaces of the siliconeadhesive and the release agent are appropriately used in theabovementioned preparation method (1) or (2) of facing surfaces.

<Configuration (a) Corresponding to a Single Layer on One Side, forExample, a Sheet Shape>

The abovementioned method (1) or (2) for preparing the facing surfacesof the silicone adhesive layer and the release layer in themanufacturing method of configuration (1) can be applied as is. Whilenot limited thereto, the method is described with reference to a sheetlaminate.

<Configuration (b), Corresponding to a Single Sided Multilayer, forExample, a Sheet or Roll Shape>

One aspect of configuration (b) can be manufactured, for example, via amanufacturing method including the following steps (1) to (3):Step (1) involving forming a release film including a release layer byapplying and curing a release coating agent consisting of the curablesilicone composition according to the present invention on a film-likesubstrate;Step (2) involving forming a silicone adhesive layer on the filmsubstrate by applying and curing a curable silicone adhesive compositionon a surface opposite the release film of the release layer; andStep (3) involving further adhering together the silicone adhesive layerand the release layer on both ends of this laminate.While the above relates to the sheet laminate, step (3) can also beperformed by winding the laminate formed via steps (1) and (2) into aroll shape. Step (3) may also be a step in which two or more laminatesproduced by steps (1) and (2) can be adhered together to form a rolledlaminate. When the outermost surface of the roll is a silicone adhesivelayer, the release film is preferably laminated further on the outerside thereof.

<Configuration (c) Corresponding to a Double Sided Single Layer, forExample, a Sheet Shape>

One aspect of configuration (c) can be manufactured, for example, via amanufacturing method including the following steps (1) to (4):Step (1) involving forming a first release film including a firstrelease layer by applying and curing a release coating agent consistingof the curable silicone composition according to the present inventionon a film-like substrate;Step (2) involving forming a silicone adhesive layer on the firstrelease layer by applying and curing a curable silicone adhesivecomposition on the first release layer of the first release film;Step (3) involving forming a second release film with a second releaselayer by applying and curing a release coating agent consisting of acurable silicone composition according to the present invention, whichis the same as or different from that used to form the first releaselayer, on a second film-like substrate that is the same as the film-likesubstrate or a second film-like substrate that is different from thefilm-like substrate; andStep (4) involving adhering together the second release layer of thesecond release film obtained by the abovementioned step (3) on thesilicone adhesive layer obtained by step (2).

<Configuration (d), Corresponding to a Double Sided Multilayer, forExample, a Sheet or Roll Shape>

One aspect of configuration (b) can be manufactured, for example, via amanufacturing method including the following steps (1) to (4):Step (1) involving forming a first release film including a firstrelease layer by applying and curing a release coating agent consistingof the curable silicone composition according to the present inventionon a film-like substrate;Step (2) involving forming a release film with first and second releaselayers by applying and curing a release coating agent consisting of acurable silicone composition according to the present invention, whichis the same as or different from that used to form the first releaselayer, on a surface opposite the first release film of the first releaselayer;Step (3) involving forming a silicone adhesive layer on the first (orsecond) release layer by applying and curing a curable silicone adhesivecomposition on the first (or second) release layer; andStep (4) involving further adhering together the silicone adhesive layerand the second (or first) release layer on both ends of this laminate.While the above relates to the sheet laminate, step (4) can also beperformed by winding the laminate formed via steps (1), (2), and (3)into a roll shape. Step (4) can also form a rolled laminate by adheringtogether two or more laminates produced in steps (1), (2), and (3). Whenthe outermost surface of the roll is a silicone adhesive layer, therelease film is preferably laminated further on the outer side thereof.

Further, in the laminate according to the present invention, thesilicone adhesive layer itself can also be configured by a laminateincluding a silicone adhesive layer on both surfaces of the substrate.In this case, the same or different two silicone adhesive layers can beused.

Such a laminate including a silicone adhesive layer having a laminatestructure can be manufactured via a method including the following steps(1) to (6).

Step (1) involving forming a first release film including a firstrelease layer by applying and curing a release coating agent consistingof the curable silicone composition according to the present inventionon a film-like substrate;Step (2) involving forming a first silicone adhesive layer by applyingand curing a curable silicone adhesive composition on a film-likesubstrate that is the same as or different from the film-like substrate;Step (3) involving adhering together the release layer of the firstrelease film obtained by the aforementioned step (1) on the firstsilicone adhesive layer obtained by step (2);Step (4) involving forming a second release film with a second releaselayer by applying and curing a release coating agent consisting of acurable silicone composition according to the present invention, whichis the same as or different from that used to form the first releaselayer, on a film-like substrate that is the same as or different fromthe film-like substrate; andStep (5) involving applying and curing a curable silicone adhesivecomposition, which is the same as or different from the siliconeadhesive composition, on the surface (the surface of the substrate)opposite the surface in which the silicone adhesive layer is provided instep (2), to form a second silicone adhesive layer;Step (6) involving adhering together the release layer of the secondrelease film obtained by the aforementioned step (4) on the secondsilicone adhesive layer obtained by step (5).

The conditions for each of the abovementioned steps are not particularlylimited as long as the curable silicone composition and the curablesilicone adhesive composition can be respectively cured to form thedesired release layer and adhesive layer. Moreover, the curingconditions of those curable compositions are well known to those skilledin the art, with optimal conditions capable of being selected withoutexcessive trial and error.

In addition to the abovementioned method for manufacturing the laminate,the laminate according to the present invention can be manufactured bysequentially creating each layer on a substrate, or by adhering togetherparts separately created on two substrates, wherein the method can beeasily considered by those skilled in the art based on common technicalknowledge.

EXAMPLES

Hereinafter, while the curable silicone composition and release filmaccording to the present invention will be described in more detailbased on examples, the present invention is not limited to theseexamples. Note that in the below-mentioned average composition formula,the symbol Me represents a methyl group, while Vi represents a vinylgroup. Moreover, the method for determining the release force uponreleasing the silicone adhesive from the release film as well as theadhesion retention ratio (also referred to as the residual adhesionratio) of the silicone adhesive after releasing the release film is asdescribed below.

<Reference Example 1> Preparation of the “Hydrosilylation CurableSilicone Adhesive Composition Solution 1”

100.0 parts by mass of a hydrosilylation curable adhesive SD 4580 PSA(solid content: 60 mass %) available from Dow Toray Co., Ltd.; 0.9 partsby mass of NC-25 CATALYST (platinum metal-containing hydrosilylationreaction catalyst) available from the same company; and 50.0 parts bymass of toluene were sufficiently mixed to prepare a uniform solution.

<Reference Example 2> Preparation of the “Hydrosilylation CurableSilicone Adhesive Composition Solution 2”

100.0 parts by mass of a hydrosilylation curable adhesive DOWSIL™7657ADHESIVE (solid content: 56 mass %) available from The Dow ChemicalCompany; 0.42 parts by mass of 4000 CATALYST (platinum metal-containinghydrosilylation reaction catalyst) available from the same company; and33.3 parts by mass of toluene were sufficiently mixed to prepare auniform solution.

<Method for Determining Release Force 1>

The curable silicone release agent composition was applied on apolyethylene terephthalate (hereinafter, abbreviated as a PET) film(available from Toray Industries, Inc., product name: Lumirror (tradename) S10, thickness: 50 μm) so as to give a thickness of the releaseagent layer of 0.2 μm after curing using a Meyer Bar, then cured byheating for 3 minutes at 150° C. to create a “release film 1” having acured silicone release layer. The “hydrosilylation curable siliconeadhesive composition solution 1” of the abovementioned reference examplewas applied on the release layer of the “release film 1” using anapplicator so as to give a film thickness of 50 μm after curing, thencured by heating for 6 minutes at 160° C. to form a silicone adhesivelayer. The PET film was adhered together on the obtained siliconeadhesive layer using a 2 kg hand roller. The obtained film was cut to awidth of 1 inch, after which the “release film 1” was pulled at a speedof 1.0 m/minute in the 180° direction using a tensile tester (RTC-1210available from Orientec Co., Ltd.), and the force (release force 1)required to release the “release film 1” from the silicone adhesivelayer at 25° C. was determined.

<Method for Determining Residual Adhesion Ratio 1>

A silicone adhesive layer of a test piece consisting of the PET filmsubstrate and the silicone adhesive layer after the determination ofrelease force 1 described above was adhered together on a 2 mm thickpolymethyl methacrylate (hereinafter abbreviated as a PMMA) plate usinga 2 kg hand roller. Subsequently, the silicone adhesive layer was pulledwith the PET film substrate at a speed of 0.3 m/minute in the 180°direction and the force (adhesive force F1) required to release thesilicone adhesive from the PMMA plate at 25° C. was determined.Separately, the “hydrosilylation curable silicone adhesive compositionsolution 1” obtained in the abovementioned Reference Example 1 wasapplied on the PET film using an applicator so as to give a filmthickness of 50 μm after curing, then cured by heating for 6 minutes at160° C. to form a silicone adhesive layer. The film was cut to a widthof 1 inch and the adhesive layer was adhered together on the same PMMAplate as described above using a 2 kg hand roller. Subsequently, thesilicone adhesive layer was pulled with the PET film at a speed of 0.3m/minute in the 180° direction and the force (adhesive force F2)required to release the silicone adhesive layer from the PMMA plate at25° C. was determined. The residual adhesion ratio 1 was determined fromthe adhesive strength F1 and the adhesive force F2 according to thefollowing formula.

Residual adhesion ratio 1(%)=(adhesive force F1/adhesive forceF2)*100(%)

<Method for Determining the Release Force 2>

The hydrosilylation curable silicone release agent composition solutionwas applied on the PET film so as to give a thickness of the releaseagent layer of 0.2 μm after curing using a Meyer Bar, then cured byheating for 3 minutes at 150° C. in order to create “release film 2”having a cured silicone release layer.Separately, the hydrosilylation curable silicone adhesive compositionsolution obtained in the abovementioned reference example was applied onthe PET film using an applicator so as to give a film thickness of 50 μmafter curing, then cured by heating for 6 minutes at 160° C. The“release film 2” was adhered together on this adhesive layer using a 2kg hand roller. This film was cut to a width of 1 inch, after which the“release film 2” was pulled at a speed of 1.0 m/minute in the 180°direction using a tensile tester, and the force (release force 2)required to release the release film 2 from the silicone adhesive layerat 25° C. was determined.

<Method for Determining Residual Adhesion Ratio 2>

An adhesive layer of a test piece consisting of the PET film substrateand the silicone adhesive layer after the determination of release force2 described above was adhered together on a 2 mm thick PMMA plate usinga 2 kg hand roller. Subsequently, the silicone adhesive layer was pulledwith the PET film substrate at a speed of 0.3 m/minute in the 180°direction and the force (adhesive force F3) required to release thesilicone adhesive layer from the PMMA plate at 25° C. was determined.The residual adhesion ratio 2 was determined from the adhesive force F2determined in the determination of the adhesive force F3 and theresidual adhesion ratio 1 according to the following formula.

Residual adhesion ratio 2(%)=(adhesive force F3/adhesive forceF2)*100(%)

<Method for Determining the Release Force 3>

The curable silicone release agent composition was applied on apolyethylene terephthalate (hereinafter, abbreviated as a PET) film(available from Toray Industries, Inc., product name: Lumirror (tradename) S10, thickness: 50 μm) so as to give a thickness of the releaseagent layer of 0.2 μm after curing using a Meyer Bar, then cured byheating for 3 minutes at 150° C. to create release film 3″ having acured silicone release layer. The “hydrosilylation curable siliconeadhesive composition solution 2” of the abovementioned reference examplewas applied on the release layer of “release film 3” using an applicatorso as to give a film thickness of 50 μm after curing, then cured byheating for 5 minutes at 140° C. to form a silicone adhesive layer. ThePET film was adhered together on the obtained silicone adhesive layerusing a 2 kg hand roller. The obtained film was cut to a width of 1inch, after which “release film 3” was pulled at a speed of 0.3 m/minutein the 180° direction using a tensile tester (RTC-1210 available fromOrientec Co., Ltd.), and the force (release force 3) required to releasethe “release film 3” from the silicone adhesive layer at 25° C. wasdetermined.

<Method for Determining Residual Adhesion Ratio 3>

A silicone adhesive layer of a test piece consisting of the PET filmsubstrate and the silicone adhesive layer after the determination of therelease force 3 described above was adhered together on a 2 mm thickpolymethyl methacrylate (hereinafter abbreviated as a PMMA) plate usinga 2 kg hand roller. Subsequently, the silicone adhesive layer was pulledwith the PET film substrate at a speed of 0.3 m/minute in the 180°direction and the force (adhesive force F4) required to release thesilicone adhesive from the PMMA plate at 25° C. was determined.Separately, the “hydrosilylation curable silicone adhesive solution 2”obtained in the abovementioned Reference Example 2 was applied on thePET film using an applicator so as to give a film thickness of 50 μmafter curing, then cured by heating for 5 minutes at 140° C. to form asilicone adhesive layer. The film was cut to a width of 1 inch and theadhesive layer was adhered together on the same PMMA plate as describedabove using a 2 kg hand roller. Subsequently, the silicone adhesivelayer was pulled with the PET film at a speed of 0.3 m/minute in the180° direction and the force (adhesive force F5) required to release thesilicone adhesive layer from the PMMA plate at 25° C. was determined.Residual adhesion ratio 3 was determined from the adhesive strength F4and the adhesive force F5 according to the following formula.

Residual adhesion ratio 3(%)=(adhesive force F4/adhesive forceF5)*100(%)

<Method for Determining the Release Force 4>

The hydrosilylation curable silicone release agent composition solutionwas applied on the PET film so as to give a thickness of the releaseagent layer of 0.2 μm after curing using a Meyer Bar, then cured byheating for 3 minutes at 150° C. to create “release film 4” having acured silicone release layer.Separately, the hydrosilylation curable silicone adhesive compositionsolution 2 obtained in the abovementioned reference example was appliedon the PET film using an applicator so as to give a film thickness of 50μm after curing, then cured by heating for 5 minutes at 140° C. The“release film 4” was adhered together on this adhesive layer using a 2kg hand roller. This film was cut to a width of 1 inch, after which“release film 4” was pulled at a speed of 0.3 m/minute in the 180°direction using a tensile tester and the force (release force 4)required to release the release film 4 from the silicone adhesive layerat 25° C. was determined.

<Method for Determining Residual Adhesion Ratio 4>

An adhesive layer of a test piece consisting of the PET film substrateand the silicone adhesive layer after the determination of the releaseforce 4 described above was adhered together on a 2 mm thick PMMA plateusing a 2 kg hand roller. Subsequently, the silicone adhesive layer waspulled with the PET film substrate at a speed of 0.3 m/minute in the180° direction and the force (adhesive force F6) required to release thesilicone adhesive layer from the PMMA plate at 25° C. was determined.The residual adhesion ratio 4 was determined from the adhesive force F5determined in the determination of the adhesive force F6 and theresidual adhesion ratio 3 according to the following formula.

Residual adhesion ratio 4(%)=(adhesive force F6/adhesive forceF5)*100(%)

[Examples 1 to 10] and [Comparative Examples 1 to 3]

Using the following components, each component was uniformly mixed inthe compositions indicated in Tables 1 and 2 to prepare curable siliconecompositions of Examples 1 and 10 and Comparative Examples 1 and 2. Notethat in the formula, Me, Vi, Fp, and Pf respectively represent methylgroups, vinyl groups, F(CF(CF₃)CF₂O)₂(CF(CF₃))(CH₂)O(CH₂)₃-groups, and3,3,4,4,5,5,6,6,6-nonafluorohexyl groups.

The following component was used as component (A).

(a1) an organopolysiloxane represented by the average compositionformula:

(Me₂ViSiO_(1/2))₂(Me₂SiO_(2/2))₂₄₅(MeFpSiO_(2/2))₁₂₀

having a vinyl group content of 0.06 mass % and a fluorine atom contentof 44 mass %(a2-1) an organopolysiloxane represented by the average compositionformula:

(Me₃SiO_(1/2))₂(Me₂SiO_(2/2))₄₄₀(MePfSiO_(2/2))₃₃₀(MeViSiO_(2/2))₁₀

having a vinyl group content of 0.20 mass % and a fluorine atom contentof 42 mass %(a2-2) an organopolysiloxane represented by the average compositionformula:

(Me₂ViSiO_(1/2))₂(Me₂SiO_(2/2))₉₀₀(MePfSiO_(2/2))₄₅₀(MeViSiO_(2/2))₁₀

having a vinyl group content of 0.16 mass % and a fluorine atom contentof 37.5 mass %

The following component was used as component (B).

(b1) an organopolysiloxane represented by the average compositionformula:

(Me₃SiO_(1/2))₂(Me₂SiO_(2/2))₅₅(MeFpSiO_(2/2))₂₅(MeHSiO_(2/2))₂₅

having a fluorine atom content of 40 mass % and a silicon atom-bondedhydrogen atom content of 0.12 mass %(b2) an organopolysiloxane represented by the average compositionformula:

(Me₃SiO_(1/2))₂(MePfSiO_(2/2))₁₂(MeHSiO_(2/2))₂₇

having a fluorine atom content of 38 mass % and a silicon atom-bondedhydrogen atom content of 0.50 mass %

(c) a 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum complex (amountof platinum metal that was 270 ppm relative to the amount of solidcontent in the curable composition) was used as component (C).

(d1) a diisopropyl ether and (d2) an ethyl nonafluorobutyl ether (Novec7200 available from 3M Japan Limited) were used as component (D).

[Mixing Test]

When the abovementioned components (a1) and (a2-1) were placed in atransparent glass vial with a lid at a mass ratio of 1:1 andsufficiently stirred and mixed at 25° C., the appearance of the mixturewas cloudy and not uniformly transparent. After the mixture was left tostand at 25° C. for 24 hours, when the appearance was visually observedagain, the mixture remained cloudy. Next, when the same operation wascarried out using the abovementioned component (a2-2) instead of theabovementioned component (a2-1), the appearance immediately after mixingwas cloudy and not uniformly transparent. Moreover, the appearance ofthe mixture after being left to stand at 25° C. for 24 hours stillremained cloudy. Note that the abovementioned components (a1), (a2-1),and (a2-2) are each independently a transparent liquid at 25° C.

A curable silicone composition was prepared according to the compositionindicated in Tables 1 and 2 below and was used as a release coatingagent to prepare the release film according to the abovementioned methodso as to determine the release force upon releasing the release filmfrom the silicone adhesive layer as well as the residual adhesion ratioof the silicone adhesive layer to the PMMA plate after releasing therelease film.

The curable silicone composition serving as the release coating agent ofExamples 1 to 10 was uniformly transparent at 25° C. Moreover, in eachcomposition of Examples 1 to 10 indicated in Table 1, when components(a1), (a2-1), (a2-2), (b1), (b2), (c), and diisopropyl ether ofcomponent (d1) were mixed so as to give a solid content concentration of10 wt. % and sufficiently stirred at 25° C., the appearance of theobtained mixture was uniform and transparent. That is, even if there isno component (d2), a uniform and transparent composition can beprepared.

TABLE 1 Compositions and evaluation results of the curable siliconecompositions of Example 1 to 10 Units of component Component amountExample 1 Example 2 Example 3 Example 4 Example 5 Example 6 (A) (a1)parts by mass 3.5 5.3 8.8 17.9 36.7 10.4 (a2-1) parts by mass 96.5 94.791.2 82.1 63.3 89.6 (a2-2) parts by mass 0 0 0 0 0 0 (B) (b1) parts bymass 0.2 0.3 0.5 1.0 2.0 0.6 (b2) parts by mass 7.7 7.6 7.3 6.6 5.1 7.2(C) (c) ppm 270 270 270 270 270 270 (D) (d1) parts by mass 869 853 821739 570 2736 (d2) parts by mass 3656 3704 3710 3803 4205 0 SiH/Vi molarratio 5.0 5.0 5.1 5.0 4.8 5.2 Determination method and determinationresults Release force 1 gf/inch 138 76 46 53 65 55 Release force 2gf/inch 18 15 25 18 11 16 Residual adhesion ratio 1 % 96 99 96 94 90 99Residual adhesion ratio 2 % 98 97 94 94 93 95 Units of componentComponent amount Example 7 Example 8 Example 9 Example 10 (A) (a1) partsby mass 4.9 9.8 19.7 29.6 (a2-1) parts by mass 0 0 0 0 (a2-2) parts bymass 95.1 90.2 80.3 70.4 (B) (b1) parts by mass 0 0 0 0 (b2) parts bymass 5.8 5.5 5.3 5.0 (C) (c) ppm 270 270 270 270 (D) (d1) parts by mass2652 2654 2659 2664 (d2) parts by mass 0 0 0 0 SiH/Vi molar ratio 5.05.0 5.1 5.1 Determination method and determination results Residualadhesion ratio 3 gf/inch 43 30 39 38 Release force 4 gf/inch 9 8 9 10Residual adhesion ratio 3 % 94 92 93 95 Residual adhesion ratio 4 % 9796 95 95

TABLE 2 Compositions and evaluation results of the curable siliconecompositions of Comparative Examples 1 to 3 Units of Compar- Compar-Compar- component ative ative ative amount Example 1 Example 2 Example 3(A) (a1) parts by mass 100 — — (a2-1) parts by mass — 100 — (a2-2) — —100 (B) (b1) parts by mass 5.5 — — (b2) parts by mass — 8.0 3.8 (C) (c)ppm 270 270 270 (D) (d1) parts by mass — 900 2600 (d2) parts by mass5213 3620 — SiH/Vi molar ratio 3.0 5.1 3.0 Determination method anddetermination results Release force 1 gf/inch 95 150 — Release force 2gf/inch 10 30 — Residual adhesion gf/inch 95 — 450 ratio 3 Release force4 gf/inch 15 — 19 Residual adhesion % 91 100 — ratio 1 Residual adhesion% 91 96 — ratio 2 Residual adhesion % 90 — 100 ratio 3 Residual adhesion% 91 — 97 ratio 4

The curable silicone compositions of Examples 2 to 8 containing thefluoropolyether-modified organopolysiloxane and the fluoroalkylgroup-containing organopolysiloxane achieves lower release force,particularly release force 1, than Comparative Examples 1 and 2. Incontrast, compared to Comparative Example 1, while the curable siliconecomposition of Example 1 had slightly higher release force, the residualadhesive force of the silicone adhesive after releasing the release filmin Example 1 was superior and the balance of these properties whenactually used in Example 1 was superior. Moreover, when Examples 2 to 8and Comparative Example 1 were compared, both the release force and theresidual adhesive force were superior in Examples 2 to 8. Moreover, bothof the release forces 1 and 2 of the curable silicone compositions ofExamples 7 to 10 achieved a lower release force compared to ComparativeExamples 1 and 3. Moreover, both of the residual adhesion ratios 3 and 4of Example 7 to 10 achieved higher values than Comparative Example 1.

When Comparative Example 2 and Examples 1 to 8 containing only thefluoroalkyl group-containing organopolysiloxane were compared,Comparative Example 2 had comparable or slightly superior residualadhesive force than Examples 2 to 8; however, the release force wassuperior in Example 1 to 8 and the practically important balance betweenthe release force and residual adhesive force was superior in Examples 1to 8 to that of Comparative Example 2. In particular, Example 2 to 8 hadmuch lower release force than Comparative Example 2, in addition tomaintaining a higher retention rate of the residual adhesive force.Moreover, when Comparative Example 3 and Example 7 to were compared,Comparative Example 3 had a higher residual adhesive force but muchlower release force. In any event, the release sheets of Examples 1 to10 have the characteristics of having a low release force to theadhesive when used as a release sheet for a silicone adhesive, alongwith a high residual adhesive force even after the release sheet isreleased from the silicone adhesive, in addition to having excellentproperties for practical use.

INDUSTRIAL APPLICABILITY

Because the release film including the release layer formed using thecurable silicone composition according to the present invention as arelease coating agent for a silicone adhesive has properties of beingable to release the release film from the silicone adhesive via weakforce, in addition to maintaining the high adhesive force of thesilicone adhesive after releasing the release film, the curable siliconecomposition according to the present invention is useful as a releasecoating agent for a release film for a silicone adhesive.

DESCRIPTION OF THE REFERENCE NUMERALS

-   1 Laminate body-   11 Substrate-   12 Release layer-   13 Adhesive layer

1. A curable silicone composition, comprising: (A) a fluorine-containingorganopolysiloxane mixture obtained by mixing the following components(A1) and (A2) at a mass ratio of 1/99 to 45/55; (A1) a fluoro(poly)ethermodified organopolysiloxane having at least two alkenyl groups permolecule along with a fluoro(poly)ether-containing organic group; (A2) afluoroalkyl group-containing organopolysiloxane having at least twoalkenyl groups per molecule along with a fluoroalkyl group having 1 to12 carbon atoms; (B) an organopolysiloxane having at least three siliconatom-bonded hydrogen atoms per molecule; (C) a hydrosilylation reactioncatalyst; and (D) an organic solvent.
 2. The curable siliconecomposition according to claim 1, wherein component (A) comprisescomponents (A1) and (A2) at a mass ratio of 2/98 to 40/60.
 3. Thecurable silicone composition according to claim 1, wherein component (B)is an organopolysiloxane having a fluoroalkyl group with 1 to 12 carbonatoms or a fluoro(poly)ether-containing organic group.
 4. The curablesilicone composition according to claim 1, wherein component (D) is asolvent mixture consisting of one solvent or two or more solventsselected from the group consisting of diethyl ether, dipropyl ether,diisopropyl ether, dibutyl ether, diisobutyl ether, di-sec-butyl ether,di-tert-butyl ether, methyl-tert-butyl ether, ethyl-tert-butyl ether,pentane, m-xylene hexafluoride, methylheptafluoropropyl ether,methylnonafluorobutyl ether, ethylnonafluorobutyl ether, and3-methoxy-1,1,1,2,2,3,4,4,5,5,6,6,6-tridecafluoro hexane.
 5. The curablesilicone composition according to claim 1, further comprising (E) ahydrosilylation reaction control agent.
 6. A release coating agentcomprising the curable silicone composition according to claim
 1. 7.(canceled)
 8. A release film comprising: a film-like substrate; and arelease layer consisting of a cured product obtained by curing therelease coating agent according to claim
 6. 9. The release filmaccording to claim 8, wherein the film-like substrate is a plastic film.10. The release film according to claim 8, wherein the film-likesubstrate is light transmissive.
 11. The release film according to claim8, wherein the release layer has a thickness of 0.5 μm or less. 12.(canceled)
 13. A laminate comprising a structure in which a siliconeadhesive layer is disposed so as to face at least one release layer,wherein the release layer is a release layer consisting of a curedproduct formed by curing the release coating agent according to claim 6.14. A laminate, comprising: a first substrate; a release layer on thefirst substrate; a silicone adhesive layer on the release layer; and asecond substrate on the silicone adhesive layer; wherein the releaselayer is a release layer consisting of a cured product formed by curingthe release coating agent according to claim
 6. 15. A laminate,comprising at least one structure obtained by successively laminatingtwo or more structure units comprising: a substrate; a release layer onthe substrate; and a silicone adhesive layer on the release layer;wherein the release layer is a release layer consisting of a curedproduct formed by curing the release coating agent according to claim 6.16. A laminate, comprising: a first substrate; a first release layer onthe first substrate; a silicone adhesive layer on the first releaselayer; a second release layer on the silicone adhesive layer; and asecond substrate on the second release layer; wherein at least one ofthe first release layer and the second release layer is a release layerconsisting of a cured product formed by curing the release coating agentaccording to claim
 6. 17. A laminate, comprising at least one structureobtained by successively laminating two or more structure unitscomprising: a substrate; a first release layer on the substrate; asilicone adhesive layer on the first release layer; and a second releaselayer on the silicone adhesive layer; wherein at least one of the firstrelease layer and the second release layer is a release layer consistingof a cured product formed by curing the release coating agent accordingto claim
 6. 18. The laminate according to claim 15, wherein thesubstrate is a film-like substrate.
 19. A laminate comprising astructure in which a first release layer is disposed so as to face onesurface of both surfaces with respect to the silicone adhesive layer,with a second release layer disposed so as to face the other surface,wherein: at least one of the first release layer and the second releaselayer is a release layer consisting of a cured product formed by curingthe release coating agent according to claim 6; and the release force(F1) upon releasing the silicone adhesive from the first release layerdiffers from the release force (F2) upon releasing the silicone adhesivefrom the second release layer.
 20. A laminate comprising a structure inwhich a first release layer is disposed so as to face one of twosurfaces with respect to the silicone adhesive layer, with a secondrelease layer disposed so as to face the other surface; wherein: atleast one of the first release layer and the second release layer is arelease layer consisting of a cured product formed by curing the releasecoating agent according to claim 6; and the release coating agentforming the first release layer differs from the release coating agentforming the second release layer.
 21. The laminate according to claim13, wherein the entire laminate is in a roll shape.